Human activities affecting body clocks of mammals, study finds

New Delhi: Human-driven activities, including climate change, could be affecting body clocks of mammals, according to a global study that found that only 39 per cent of the species are behaving in line with what previous research says.

Further, because of the environmental changes and the resulting effects, a majority of previous research related to body clocks of mammals could be outdated, researchers, including those from The University of Sydney, Australia, said.

All animals are known to have circadian rhythms, or body clocks, regulating activities over a 24-hour period -- also called diel cycle. Collectively, the rhythms can develop into a generalised behaviour for a species.

However, climate change threatens to upend these established patterns with unexpected consequences, the researchers said.

For their analysis, published in the journal Science Advances, the team analysed video camera footage of 445 mammal species to note activity patterns over a 24-hour period.

Results were compared with previous studies.

"Through a global network representing 38 countries, we leveraged 8.9 million mammalian observations to create a library of 14,587 standardised diel activity estimates for 445 species," the authors wrote.

"Overall, we found only 39 per cent agreement between our results and reference classifications, which further suggests that we need to re-evaluate species diel behaviour to fully understand their niche and how to conserve them in an anthropogenic world," they said.

The team looked at whether circadian activity was responsive or resistant to environmental changes.

The species showed a high plasticity in their diel patterns, indicating an ability to adjust daily activity depending on environmental conditions, the authors said.

Finally, among a selected 126 species, the team studied how geography affected diel plasticity.

"Distance from the equator, daylight hours per day, and exposure to human activity influenced diel phenotypes for 74 per cent of these species," they wrote.

Data for the study was taken from the Global Animal Diel Activity Project, which includes 217 collaborators from 20,080 camera sites across 38 countries.